Friction clutch



Jan. 2, 1945. H. NUTT FRIcToN CLUTCH Fild Mrch so, 1942 5 Sheets-'sheet 1 Jan.; 1945. H, Nw` 2,366,643

FRICTION CLUTCH Filed March 30, 1942 5 Sheets-Sheet 2 Jan. 2, 1945.

H. NUTT FRICTHION CLU-TCH Filed March 30, 1942 5 Sheets-Sheet 5 Patented Jan. 2, 1945 attains.` Farc'rroN CLUTCH Harold lilutt,l Chicago, Ill., signor to Borg-War- Crporation, Chicago, Ill., a corporation `of o t fu Appleman March so, l1942, serial No. 436,853

momma. (ci isz-es) -This invention rente-sto friction clutches and has as its general object-toprovide an improved heavy duty" 'clutch suitable for use in military tank transmissions and the like.

Specifically; the invention aims improve upon j 'an arsenal clutch` of a`typ`e adapted forus'e with an Vengine having a. capacity of about 840 foot pounds torque, wherein clutch disengaging pressure is applied from a pair of rollers carried by anoperating lever, toa radial flange of a clutch operating collar which is splined upon a sleeve at the center of the clutch cover. In such a clutch Y organization, the operating collar rotates with the c1utch,` and there is relative rotation between the collar and the operating lever, but none between the collar andthe several release levers which transmit the pressure from the release `collar to the pressure plate.

One of the specic objects of 'the invention is to eliminate wiping contact between the operating lever rollers and the operating collar flange, so as to reduce wearing of the roller and ilange to a minimum; In this connection, the invention aims to'provide a clutch `capable of carrying a load of 1250 foot pounds torque,` in which the load upon the operating collar may safely exceed 650 pounds. Under such heavyloads, the problem of wear between the operating lever andthe operatin'g c'ollar is a major one.

Another4 object or' theinvention is to provide an `improved antifriction connection between the `operating collar and the clutch levers. A further object of the invention is to provide an improved arrangement for restraining undesired movement of the clutch leverswithout interfering in'r any way with the free operation of the levers.

Another object of the invention is to provide an improved arrangement-,whereby the clutch levers may be initially adjusted to a parallel setting and may, after a period of wear on the driven in tensile strength.

Other objects, advantages and uses of the invention will become more apparent after reading the following specication and claims,'and after consideration of the drawings forming a part of the specification, wherein:

Fig. 1 is an axial sectional view of a clutch bodying my invention; Fig. 2.is atransverse sectional view o! a portion of the same, taken on the line 2-2 of Fig'. 1;`

Fig. 3 is a detailed sectional view or associated portions* of the operating lever and operating col,-

lar, taken on the lineal-3 oiFlg. 1;` i l Fig. 44 is a detailed viewof the wear-in shim;

Fig. 5 1s a detailed VView of the mimi adjust-' ment shim; y

Fig. 6 is an axial sectional view of a two plate clutch embodyingthe invention;

Fig. 7 is a detailed sectional view of a modified arrangement of voperating lever and operating'collar; and

Fig'. 8 is a detailed sectional viewof a portion of the clutch of Fig. 1, taken on the `line 8-8 of As an example of one form in which the invention may be embodied, I have shown in Figs. l-to 5 inclusive a single plate clutch embodying a.

flywheel I0 bolted at I2 upon the il'anse i4 of a hub IB which 'is internally splined for driving connection with the crank shaft ILThe ywheel ill has at its" periphery a rim 20 to therear face of' which is bolted at 22, the cover 24.` The ywheel i0 is provided with a friction face 28. -Deilned between the cover 24 and the flywheel I II isan annular chamber 21 in which is receivedthe an.

Lubricant isV sealed within the hollowinterior of Y the driven shaft 42 by a sealing ring 46 cooperating with the bearing 44.

The cover `24 includes a-hub sleeve 48 and a radially extending disc portion 50. Clutch packing springs 52 are interposed between the pressure plate 28 and springsocket cups which are set into openings 56 in the disc member.

The disc member is made of quite thick materialin order to adequately withstand. without distortion the heavy loads developed inthe clutch. It is made of pressed steel inorderto adequately withstand centrifugal forces developed init. Because of its thickness, however, it is impracticable to form it integrally with the hub sleeve 48 and 55 accordingly, the disc Slis formed as a separate 88, which engages the rollers 16.

12 to a portion of the frame of the vehicle hasy a pair of furcations 14 on the ends of which are Journalled rollers 18. The rollers 18 are arranged to engage the flange 88 at diametrically opposed points, and are journalled, through the medium of bearings 18 on trunnions 80 mounted in the furcations 14.

In the earlierclutches 4of this type, considerable wear was encountered in theengaging surfaces of the rollers andthethrow-out collar flange. the fact that the surface of the collar flange against "which the rollers engaged was flat and `made a. line contact with the rollers, resulting I have concluded that thiswas due to.

face |08 maintains the region of contact between the linger |08 and-the lever end 94 in substantially the same position on the finger |06. The finger |08, by preventing spreading movement between the linger |02 and the end portion 94 of the lever, eliminates any possibility of the strut Y 98 becoming displaced from the depressions |0| and |04.

Thrust is transmitted from the sleeve 62 tothe inner ends of the levers 82 through the medium 1 of a radial flange ||0 on the forward end of the collar 62, and a strut ||2 interposed between the flange ||0 and each of the levers 82. 'I'he inner end ||4 of each lever 82 is widened circumferentially 'and provided with a notch ||6 in which one end of thestrut I I2 is cradled. Theother in a wiping action between the rollers and the flange. Such wiping action would arise as a result of the dierence in linear speed between the outer'and inner regions of the ila-nge surface in contact with'the rollers, `and the constant linear speed oi' all Vportions of the roller surface.

The present invention remedies this difllculty.

by crowning as at 69 the surface of the flange As a result, the rollers .16 engage theA flange 68 at only one radius, and wiping action is eliminated. y

An alternative solution of the problem is to crown the surface of the rollers 16 as at 16a in Fig. '1, permitting the coacting surface of the flange 88a to be flat as shown. The effect is the same, i. e. the-roller contacts the flange at only one radius of the latter, and wiping action is eliminated. If desired, both roller and flange may be crowned. 1

Clutch v.disengaging pressure is transmitted from the collar 62 to 'the pressure Vplate 28 through the medium of clutch operating levers 82. The levers 82 are pivoted through the medium of anti-ffrlction bearings 94, on. pins 86, which are` each mounted in a pair of circumferentlally spaced ears 88 formed on the pressure v plate 28. Each pair of ears 88 is formed as the terminal portions of a driving lug 90, which ex- 'I'he brackets 98 and the cover 24 are both secured to the rim 20 of the flywheel by the samebolts |38. Each strut'98 is engaged at one end in a depression |0| in a finger |02 on the bracket 98, and at its other end in a depression |04 in the outer end portion 94 of the lever 82. Thus the strut is confined against radial movement. The finger |02 extends between the ears 88. Thus the strut is coniined'between the ears 88 against Y circumferential movement.

The outer end portion 94 of the lever has a crowned` rear ,surface |08 and is restrained against movement away from ythe nger |02 by end of the strutis received in an annular groove I8 in the rear face of the flange |0. The groove ||8 is of sufllciently greater width radially than the thickness of the struts ||2 to accommodate the chordal positioning of the struts therein. I

Each strut I2 is positioned circumferentially by a pair of fingers |20 (seevFig. 8) on thestrut .embracing the adjacent region of the end portion ||4 of the lever. v

Undesired movement between the inner ends ofthe levers and the collar 62 is restrained by a restraining flange |22 on the collar 62, cooperating with crowned surfaces |24 on the inner end portions ||4 of the levers.A As at the outer ends of the levers, by thus preventing the levers and iiange I|0 from spreading apart, I eliminate y any possibility ofthe struts ||2 becoming displaced from the depression ||8 or groove I I8.

The struts 96 and ||2 function to transmit Vthrust between lthe arcuately swinging end portions lof the levers 82 and the collar 82 and bracket 98' respectively without the development of wiping action. The fingers |06 and flange V,|22 cooperate to maintain the parts in assembled relation and to prevent any substantial amount of lost motion inthe linkage. The employment of struts makes it possible to `successfully use lost ,motion restraining members which are rigidly associated with the throw-out collar and The levers 82 cover bracket respectively. Assembly of the parts is made possible by employing brackets 98 which areseparate from the cover 24. and which' may be secured thereto after assembly of the struts 99 and the outer ends 94 of the levers between fingers |02 and |06 has been effected. This op'- 4eration is the last step in the assembling of'the linkage, and is made possible by the provision Y of relatively wide shim spaces between the brackets 98 and the cover 24. In orderto make. these points clear I will now briefly describe the comple'teoperation of assembling the linkage.

a restraining finger |08 formed on the bracket fr YHaving first assembled the driven plate 32 and pressure plate 28 loosely between the flywheel |0 and cover 24, with the packing springs 52 and retainer cup 54 in place, pressure is brought to bear against the cover 24 bya suitable arbor press or the like until the springs 52 have been compressed sutllciently to permit the cover to make contact with the rim 20 of the flywheel. ,During this step in the operation, the ears 88 are guided through the openings 92 in the cover. The levers 82 Vare then inserted between the ears 88 and the bearings 84 and pivot pins 88 are assembled. The inner ends of the levers are then moved away from the cover 24 until their arcs of swing brin-g them raidally outwardly of the outerv diameter ofthe flange ||0 of the collar 62. The

collar 62 is then slipped over the cover hub sleeve 48 and advanced between the ends of the levers l ings.

to a position in which the flange H3 has cleared the inner ends of the levers. The struts ||2`are then assembled in the notches IIS in the ends of the levers, and the,levers are swung toward the coverwhile the struts ||2 are manipulated into the groove ||8 in the collar flange H0. 'I'he collar 62 is then moved toward the cover andthe `'ends ||4 of the levers are manipulated intothe annular space between the flanges ||3 and |22,V

' space betweenthe outer end 34 of each lever 32 andthe cover. The brackets 88 and struts 33 arethen applied, the struts and lingers |02 being nrst inserted between the ears 88 while the outer `portions of the brackets are in directcontact with the cover,the brackets being then manipulated so as to slidethe fingers |38 over theend portions 94 of the levers. During this manipulation the brackets will be moved away from the cover, leaving spaces which are filled by the shim mechanism now to be described.

y Between each bracket 98 and cover 24 is' in-V cluded' a plurality of shims |28 and |28 respectively." The shims |28 have lholes |33 in their respectiveends. The brackets 88 haveears |32 provided with correspondingly positioned open#v 'I'he shims |28 each have a holeg|34 at one end and a notch `|33 at tlie other end..` Bolts |38 are Vextended through the ears |32, the holes |33, the holes |34, and notches |33, and threaded into the rim ofthe flywheel. The bolts |38 sey cure all parts. of

the clutch in assembled relationship.

, .-I employ one of the shims |28 and one or more of the shims |26under each bracket. 83.` The shims |,2B are of varying `thickness and are se-` 4lecteci so as to ,line up the vlevers 32 in parallel relationship, i. e., with their inner ends uniformly related to the iianges H0 and I 22 of the throwout collar. The shims |28 have a uniform thickness which is determined by the amount of wear to be taken up in the clutch after a predetermined period of operation has-expired. Each of the shims |28 has at one end a tab |40'provided with a'screwdriv er slot |42. Adjustment for Vwear may be made quickly and easily by removing the boltsr|38 which extend through the openings |34, loosening the remaining bolts |38, inserting the end of a screw driver inV each slot |42, and sliding the shims w|28 from beneath the brackets 88. The notches` |36 permit the shims Vto be thus pulled out when the bolts are removed from the holes` |34, while the shims |26 remain pinioned upon the remaining bolts. When the shims |28 are detached, the removed bolts are replaced and thecoverassembly tightened down against the flywheel. This operation effects a takeup of the wear that has taken place in the clutch, without disturbing'the parallelism of. the levers which was initially effected by the insertion of the shims |26. Thus the clutch can be quickly and easily adjusted in the field without disturb ing the proper operative positioning of its parts.

The dotted lines |46 and |41 indicate the hub portion of a fan employed for cooling the engine of a tank in which the clutch may be embodied,

The clutch shown in Fig. 6 involves all of the novel features pointed out above, differing from the previously described clutch in having two said. lever ends and struts.

3. 4A clutch as dened in claim 1, 'wherein said4 one member includes a pair' of ears between which said lever is pivoted, said strut being positioned driven plates 32a and two pressure plates 28a and 28brespectively and a separate friction facing ,34a bolted to the flywheel bybolts |43. The cover `24a is also changed, beingin the form of a steel `casting with the spring pockets 34a integri-.my formed therein, The bolts m m this.

form of the invention do not extendinto the flywheel. "The cover is secured to the ywheel by separate bolts |38a. Thus the brackets 38 are separatelymounted on,the cover and the cover, with the brackets attached, may be disassembled" as a unit without disturbing the set-` ting of thebrackets. In all other respects this clutch is the Asame as the one previously described landthe same reference characters are used to- Vdesignate the parts thereof.

1. In a heavy duty friction clutch, in combina-l tion with a pair of clutch members 'drivingly connected together and axially movable with reference to each other, a lever pivoted on one of said members and having an'outer end portion fulcrumed with reference to the other of said members, the fulcrum means comprising a bracket on said other member having apair of integral spaced elements one `of which is in close juxtaposition to one side fof said lever endportion, -and a swinging fulcrum. strut interposed. between the-other side of said other of said elements. y

2. Aclutch as defined in claim l, wherein said brackets are separate from said other member and spaced therefrom by shim meanswhich when removed permits the brackets `to be manipulated for assembly and; disassembly with reference to between said ears and therebyconflned against cricumferential movement.

4. -A clutch as defined in claim l, wherein said v one member includes a pair of ears between which said lever is' pivoted, said lever end'and said strut-engaging element having recesses in which the respective-ends of said strutare receivedso as .to confine said strut against radial movement, said'recesses' being located within the spacebetween said ears so as to confinesaidstrut between saidears against circumferential move-` ment. Y i 5. In a friction clutch, a flywheel and pressure plate adapted to engage adriven member between them, a cover on said` flywheel defining therewith an annular space in which said pressure plate is received, said cover having an opening and vsaid pressure plate having a driving lug extending through .said opening, said ,lug terminating in a pair of circumferentially spaced ears. a releasel lever pivoted in said ears, a bracket detachably secured to said cover and flywheel, said bracket having a pair of integral radiallyinwardlyrextending axiallyvspaced ngers, one of which extends intothe space between'saidiears and is provided therein with a recessfacing the outer end of said lever, said outer lever end having a recess facing `said recessed iingerand located in the space betweensaid ears, astrut the respective ends of which are received in said recesses and thus confined against radialmovelever end portion and the movement.

and said recessed flngersuch as would permit the strut to become displaced from said recesses.

6. A clutch as defined in claim 5, wherein said bracket isdetachablysecured to said cover and spaced therefrom by spacing means which when removed permit the manipulation of said bracket into and out of assembled relationship with said `strut and lever end.l

7. In a friction clutch,' a pair oi' clutch members adapted to engage a clutch element between them, one of said clutch members having a pair of circumferentially spaced ears, a lever pivoted between said, ears and having a recessV disposed between said ears, an element carried by the other of said members, extending between vsaid d3. In a friction clutch, a clutch member having Y ahub sleeve, a clutch operating collar axially Vsl dably and non-rotatably mounted on said eeve, said collar having a radial flange, a clutch l ver having an inner end opposed to said iiange, nieans on which said clutch lever is pivoted'on anaxis at a distance radially from the clutch axis, and a thrust transmitting strut interposed between said inner end of the lever and said ange, `adapted to effect substantially non-frictional transmission of thrust from said collar to said lever.

10. A clutch as deflned'in claiml9, wherein said ange has an Vaxially facing annular groove in which one extremity of said strut is conned against radial movement. Y n

' 11. A clutch as defined in claim 9, in which Vsaid inner lever end has a notch in which one extremity 'of said strut is confined against radial 12,'A clutch as defined in claim 9, whereinv said iiange hasY an axially facing annular groove in which one end of said strut is confined against radial movement and said lever has an axially facing notch opposed to said groove, in which the tion said strut' against circumferential movement.

14. A clutch as defined in claim 9, wherein said flanges and lever ends are provided with'opposed recesses in which the respective ends of the struts are received and positioned against radial movee ment and in which said collar is provided with a *second flange coo rating with the rst mentioned flange to de ne an annular space in which said leverend and strut are`confined against axial displacement with reference to said first mentioned flange.

15. A clutch as deflned in claim 9, wherein said ving movementbetween said lever end portion flange is provided with an axially facing annular groove in whichone end ofv said strut is connned Y against "radial movement, saidrinner end of the lever is provided with a notch in which the other end of said strut is confined against'radial movement, said strut includes a pair of circumferentially spaced fingersembracing said lever so as to position said strut againstcircumferential movement,` and said collar is provided with asecond flange spaced from said first mentioned flange to provide an annular space in which said inner end of the lever and said strut are .confined against axial displacement with reference to saidA one yof said brackets, means for transmittingl thrust to the inner ends of said levers, andspacing means interposed between said` brackets and said one member, said spacing means including a plurality of wear take-'up shimsvoi' vuniform thickness, one for each of the brackets, and a plurality of shims lfor effecting initial adjustment of the levers, said take-up shims being adapted to be removed while the" adjustment shims remain,

whereby to correct for wear in the Yclutch withoutl disturbing the positional relationship of the levers and said thrust transmitting means.

1'7. A clutch as defined in claim 16, wherein i said brackets are'each provided withva pair of spaced openings, said initial adjustment shims are provided with a pair of .correspondingly Y spaced openings and said `take-up shims are each provided with an opening and a notchcorref sponding to the aforesaid openings.

18. A clutch as defined in claim :16,V wherein lsaid wear take-up shim is provided with a'tab sure plate is received, said cover having an openv Ving and said pressure plate having la projecting portion extending through said opening, a release lever pivoted on said projecting portion, a bracket against which the outer end of said lever is fulcrumed, said bracket being detachably secured to said cover by means not directly connected with the iiywheel, and separate means attaching said cover to the flywheel.

20. In a friction clutch, a flywheel andipressure plate adapted to engage a driven member between them, a cover on said flywheel defining therewith an annular space in which said presr sure plate is received, said cover having an opening, said pressurev plate vhaving a projecting portion extending `through said opening, a plurality of fulcrum brackets secured to said cover `by means not directly connected with said flywheel, separate means connecting said cover to said flywheel, levers pivoted on said projecting portion and fulcrumed against said brackets, and spacing means interposed between said brackets and said cover, said spacing means including a plurality of wear take-up shims and aplurality of shims for effectingiinitial adjustment of the levers.

' f' HAROLD NUTT. 

